Small-Scale Mix in Direct-Drive Cryogenic DT Implosions on OMEGA*

Mix on scales below the spatial resolution of conventional x-ray imagers (5 to 10 μm) in direct-drive cryogenic DT implosions on OMEGA is studied using time-gated (~20 ps), narrowband, soft x-ray (1865 eV) backlighting. The large opacity difference between DT and the carbon from the plastic ablator, which encapsulates the DT ice layer, makes this radiography setup very sensitive to ablator material mixed into the DT close to peak neutron production. The radiography data shows a strong correlation of the mix signatures with the adiabat (α = P_shell/P_fermi) and the in-flight aspect ratio of the implosion design. Details of the radiography setup including work to improve the brightness of the backlighter and the spatial resolution of the imager will also be presented.